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Wooden support posts are available in shaped sizes, as engineered products, and as timber posts. The shaped sizes are described by their nominal dimensions, such as 4 in X 4 in (100 mm X 100 mm). This is their size prior to the surfacing required to provide smooth and straight posts. Their actual size is […]

The steel U-channel support is the most common type of single sign support used in the United States [19]. The steel U-channel is a unidirectional support available in different sizes and stiffnesses from a variety of manufacturers. The most popular steel U-channel sizes are 2, 2.5, 3, and 4 lb/ft (3, 3.7, 4.5, and 6.0 […]

The only types of sign-support systems that should be used are those that have been approved for use by the FHWA. The following concerns should be addressed in the selection of an appropriate single-sign-support system: • The specifications for support size provided by many states provide information on the maximum sign panel area to be […]

Sign assemblies consist of four components: • The sign panel on which the message is displayed • The signpost • Mounting hardware and fasteners • The base for the post Sign Panels. The majority of sign panels in use today are made from sheet alu­minum stock [19]. The thickness of the stock varies depending upon […]

Traffic signs are a primary source of information to motorists. The majority of traffic signs consist of sign panels held in place by a single support. Single supports can usu­ally be used for signs as large as 18 ft2 (1.7 m2) in area. The only purpose of the sign support is to hold the sign […]

Breakaway supports are designed and evaluated to operate safely on the basis of the char­acteristics of the vehicle fleet. One of the primary characteristics included in discussions of the impacting vehicle is its weight. While weight is very important, the bumper height is equally important, since it establishes where the vehicle weight is first concentrated […]

The sign panel, the support, and the embedment or anchorage system are the three components of a sign assembly. Each component contributes to the effectiveness, structural adequacy, and safety upon impact of the device. The sign assembly must be structurally adequate to withstand its own weight and the wind and ice loads subjected to the […]

Estimates on the number of signs present on our roadways vary drastically. An NCHRP synthesis indicated 58 million signs, while a study for the FHWA estimated that there are approximately 250 million sign assemblies on the U. S. roadway system [15, 16]. Signs contribute an important role in increasing the safety of the roadway by […]

The need for traffic signs, roadway illumination, utility service, and postal delivery results in roadside features frequently placed within the roadway right-of-way. (Also see Chap. 6, Safety Systems.) The presence and location of these obstacles varies by roadway type and location. Rural freeways, for example, can be designed where traffic signs are the only obstacles […]

A large number of supplemental advance warning devices have been used by roadway agencies to inform motorists of unusual geometric, operational, or traffic control fea­tures. The use of a device by an agency does not imply that it is a viable or desirable device to use for identified deficiencies. The following concerns should be considered […]